Vulnerability Intelligence Report
Prefix escape
CVE-2021-21321
fastify-reply-from is an npm package which is a fastify plugin to forward the current http request to another server. In fastify-reply-from before version 4.0.2, by crafting a specific URL, it is possible to escape the prefix of the proxied backend service. If the base url of the proxied server is "/pub/", a user expect that accessing "/priv" on the target service would not be possible. In affected versions, it is possible. This is fixed in version 4.0.2.
No Active Exploit Signals
CVSS Base Score
10.0
CRITICAL
Exploitability:3.9
Impact Score:5.8
EPSS Probability:1.82%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
—
Weaknesses (CWE)
CWE-20 ↗CWE-20 Improper Input Validation
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| fastify | fastify-reply-from | < 4.0.2 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
1.821%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2020-12-22T00:00:00 |
| Published | 2021-03-02T03:35:25 |
| Last Updated | 2024-08-03T18:09:15 |
Community Chatter & Buzz